The Summoner's Circles

Monsters spawn from the circle's center of haywire magics. It brought the charagma into this world, and it steal away the energies from other planes.

Purpose / Function

Long ago, These Summoner's Circles were built by mages: some were built as a challenge from the gods who would offer their chosen people or others a chance to fight otherworldly beings, face trials, and thusly prove themselves; others were built as a challenge to the gods as the summoner's circles were designed to bleed other realms of their power, thusly handing it over to the summoner. Whatever the case, these circles have long since lost their masters.
Now, without an attendant, the siphoned magics curse and strike out at the surrounding land. While others may still find gods amiable and willing to converse through them, other will be cruel, and some now ignorant (complacent, even!) of the matter long past.

Alterations

Some of the Summoner's Circles are maintained by nearby mages as an act of civil service to the towns in which they reside, usually nearby such a structure. They only interact with the ring as a means of deactivating it when the magics begin to react. This is to prevent a conjunction.
Other cities that are far away from summoner's circles will sometimes form an allied garrison that is in charge of monitoring and exterminating beasts that spawn from the ring. Some of these garrisons will erect walls around the circles, employ mages, or use those that spawn at the circle for menial labor. Other times, these matters are tended to by local covens of druids.

Architecture

Overall, Summoner's Circles must lay on a flat plot of land, they are no bigger than 1 and (1/4) kilometers in diameter. Additionally, they are usually sectioned off with boulders, pillars, or small outer spires, with an obelisk in the center. More ornate rings will take on the characteristics of the plane to which they are connected.
When a summoner's circle is no longer contained by an outer ring, either due to negligence or weathering, their influence will stretch farther into the world, usually no further than a 24 kilometer diameter as long as the obelisk prevails.
Attempts have been made to destroy some of the Summoner's Circles Obelisks, and, due to the knowledge of how to do so properly being lost except to the most hermatic of sages, they often cause a rift or a break in the land, the most notable being the Scar of Akrasia. Since then, efforts to alter the architecture have halted.

Alternative Names

Spawners, Rings

Type

Megastructure, Land based